Galvanizing flux



United States Patent 3,321,339 GALVANIZING FLUX William A. Schulze,Parma Heights, Ohio, assignor to E. I. du Pont de Nemours and Company,Wilmington, Del., a corporation of Delaware No Drawing. Filed May 7,1965, Ser. No. 454,211 6 Claims. (Cl. 148-23) This invention relates tothe galvanizing fluxes and is more particularly directed to compositionsadapted to be used in a flux wash consisting essentially of a fluxingmaterial such as zinc ammonium chloride modified with an alkyl sulfonateand the condensation product of oleyl alcohol with ethylene oxide.

It is customary to prepare metals prior to galvanizing and prior tointroduction into a molten metal bath by passing them through an aqueoussolution which is called a flux wash. Such solutions customarily containfluxing materials such as zinc chloride, ammonium chloride, and zincammonium chloride.

It is important, especially in some of the new high-speed continuousgalvanizing processes, that the flux wash thoroughly wet the surface ofthe metal and yet the solution must not foam excessively. If there isany considerable foaming in the flux wash, the high speeds at which themetal is traveling cause an excessive dragout from the flux wash bath.When foam is carried out 7 on the metal this gives a very uneven layerof flux thickness and as the foam breaks there are thin spots whichresult in poor galvanizing.

It has been proposed in Speed et al. US. Patent 2,879,195 that excessivedrag-out be diminished by the use of an alkyl sulfonate. Such fluxeshave been used commercially with success. However there is often agreasy dispersed phase which separates and rises to form an oily scum.This greasy material is quite objectionable and will often collect intowaxy agglomerates of considerable size which float on the surface of theflux and interfere with galvanizing. Metallic hydroxides also tend to begathered into the waxy agglomerate and this further interferes withgalvanizing.

As described in Speed US. Patent 2,829,077 a similar effort Was made tosolve the problem of excessive dragout by using a condensation productof oleyl alcohol with ethylene oxide. Flux washes containing thismaterial were comparable in activity to those of the Speed Patent2,879,195 but had a somewhat greater tendency to form a foam.Accordingly they are less attractive commercially.

Now I have found that by using a small amount of a condensation productof oleyl alcohol with ethylene oxide as shown in Speed 2,829,077 in theflux wash compositions of 2,879,195 there are obtained flux washes whichare substantially free of the dispersed insoluble oily materials whicheventually form scum and interfere with operation of the fluxes of Speed2,879,195. Flux washes as thus modified do not gather metallichydroxides into a Waxy mass but rather the metallic hydroxides settle tothe bottom of a tank containing the flux wash from which they canreadily be separated. Flux washes containing both the alkyl sulfonateand the oleyl ethylene oxide condensation product are very low foaming,stable in use, and are homogeneous solutions.

The improved flux wash compositions of this invention can be preparedwith a fiuxing material such as ammonium chloride, zinc chloride, zincammonium chloride, and other such flux compositions. Most preferred forflux wash compositions of the invention are the socalled high ratio zincammonium chlorides. These are flux compositions in which the weightratio of ice ranges from 1.27:1 to 1.35:1. These are normally made upinto prewash fluxes of about 12.2 Baum strength and used at temperaturesaround F.

The prewash flux compositions of the invention are made up by theaddition to one of the flux materials described, and preferably to ahigh ratio zinc ammonium chloride, of a small amount of an alkylsulfonate. The alkyl sulfonate has the formula:

in which R is a higher alkyl group ranging from about 8 to 18 carbonatoms.

The commercially available material which is preferred contains minoramounts of sodium sulfate and sodium chloride and R is approximately Cwhich corresponds to the kerosene fraction. The SO Na groups arerandomly distributed. A preferred range of commercially availablematerials are those made from a hydrocarbon fraction of 12 carbons to afraction which is about 16 carbons.

As described above, the composition containing an alkyl sulfonate ismodified by the inclusion of a copolymerization product of oleyl alcoholwith ethylene oxide. The oleyl alcohol used is preferably the technicalgrade which is a mixture of saturated and unsaturated alcohols rangingfrom about '8 to 22 carbon atoms and prepared by the sodium reduction ofa suitable oil such as, preferably, sperm oil.

The oleyl alcohol is reacted with ethylene oxide as shown in Schoellerand Wittwer US. Patent 1,970,578, dated Aug. 21, 1934. About 10 mols ofethylene oxide are used for each mol of oleyl alcohol. This canobviously vary somewhat, say, from 8 to 12 mols, though it is preferredto use 10 mols.

In making flux compositions of the invention the alkyl sulfonate and theoleyl alcohol-ethylene oxide condensation product can be mixed togetherand the mixture applied to the dry flux material if it is to be sold indry form. The materials can of course be added separately if moreconvenient. The sulfonate is commercially available as a 20% solution inwater and the oleyl alcohol condensation product is a waxy materialwhich can be dissolved in the solution if it is wished to add themtogether. It is somewhat preferred that the materials be thus mixed andthen added together because there is a tendency for the oleyl alcoholcondensation product to gel and this is prevented.

The flux materials are frequently sold as aqueous solutions and in thisevent the additives can simply be dissolved in a solution of thematerial. Thus high ratio zinc ammonium chloride is customarily sold asa 58% solution in water and the mixture prepared as above is preferablyadded to this solution.

The amount of the alkyl sulfonate to be used can be varied widelydepending upon the flux material and upon the effect desired. Generallythere will be used from about 0.04 to 0.4 gram, computed as sodium salt,of alkyl sulfonate per hundred gram of zinc ammonium chloride or of theother fluxes mentioned. Less than this does not have the desiredmagnitude of effect and the use of more is wasteful.

The alkyl sulfonates are sold commercially as the sodium salt and whenreference is made herein to the use of an alkyl sulfonate this canconveniently be the sodium salt or if desired a potassium salt oranother soluble salt. The products can of course be used as the alkylsulfonate without forming the salt and all can be considered asequivalent for purposes of the present invention.

The amount of the oleyl alcohol-ethylene oxide condensation productdepends upon the amount of the alkyl sulfonate. Broadly, the proportionis such that the ratio of alkyl sulfonate:oleyl condensation ranges from0.2:1

to 4: 1. More narrowly it is preferred that the ratio range from 1:1 to2:1 in commercial practice.

When reference is made in the claims to a galvanizing flux it will beunderstood that this can be dry, can be a concentrate suitable fordilution to form a flux Wash at the place of use, or can be the diluteflux wash at a concentration suitable for use.

In order that the invention may be better understood reference should behad to the following illustrative examples:

Example 1 Four parts by weight of an alkyl sulfonate was placed in areceptacle in the form of a 20% solution in water. The alkyl sulfonatecontains sulfonates of the formula in which the SO Na groups wererandomly distributed and in which R approximates C (kerosene). Theproduct contained minor amounts of sodium sulfate and sodium chloride aswell as a small amount of unreacted alkane. It was used as the sodiumsalt.

To the aqueous solution there was added two parts by weight of meltedcondensation product of ethylene oxide with oleyl alcohol. The oleylalcohol used is a mixture of saturated and unsaturated alcohols of 8 to22 carbon atoms. This is sold commercially as technical oleyl alcohol.The technical grade oleyl alcohol was a mixture of saturated andunsaturated alcohols obtained by the sodium reduction of sperm oil andhad the following approximate composition:

Percent C saturated 3.23 C unsaturated 2.87 C saturated 12.55 Cunsaturated 19.65 C saturated 7.7 C unsaturated 42.8

C saturated C unsaturated 7.1 C saturated 0 C unsaturated 4.1

The oleyl alcohol was reacted with mols of ethylene oxide for each molof alcohol as shown in Us. Patent 1,970,578.

The two materials were mixed to form a clear solution. The six pounds ofmaterial was then dissolved in a 58% aqueous solution of zinc ammoniumchloride which contained 10,000 pounds of the zinc ammonium chloride.The zinc ammonium chloride had a ZnCl zNH Cl ratio of 13:1.

The product thus produced is clear and substantially free from dispersedinsoluble material. Any precipitate of metal oxides or hydroxidesseparates to the bottom. The solution as thus prepared can be sold as aflux wash concentrate and a customer will use it by adding water in theamount desired, usually about an equal quantity depending upon thecustomers preference. The flux wash thus prepared can be used in thecustomary manner and gives excellent results with negligible foaming andwith even galvanizing of excellent quality.

The ratio of the sulfonate to the oleyl-ethylene oxide condensationproduct is 2:1 in the above example.

zinc ammonium chloride can be 0.4 or any intermediate figure with theratio of sulfonate to oleyl condensate being 0.2:1, l: 1, 2:1, 4:1 orany intermediate figure. Likewise the zinc ammonium chloride used abovecan be replaced in each of the possibilities described with zincammonium chloride of a diiferent ratio or with ammonium chloride or zincchloride.

Example 2 A 20% solution of the alkyl sulfonate of Example 1 in anamount to contain 4 parts by Weight of sodium salt of alkyl sulfonatewas used to dissolve 2 parts by weight of a condensation product ofoleyl alcohol with ethylene oxide as in Example 1. The mixture is thensprayed upon 10,000 pounds of zinc ammonium chloride, the zinc ammoniumchloride having a ratio as described in Example 1.

A similar procedure can be followed with the same components but simplymixing the zinc ammonium chloride and the wetting agent by dumping theminto the hopper of a mixing screw in which thorough mixing is effected.

I claim:

1. A galvanizing flux consisting essentially of a fluxing materialselected from the group consisting of ammonium chloride, zinc chloride,and znc ammonium chloride and 0.04 to 0.4 gram, computed as sodium saltof an alkyl sulfonate per grams of said fluxing material and thecondensation product of oleyl alcohol with about 10 mols of ethyleneoxide the ratio of said sulfonate to said oleyl alcohol condensationproduct being from 0.211 to 4:1.

2. A galvanizing flux of claim 1 in which the fluxing material is zincammonium chloride.

3. A flux composition of claim 2 in which the ZnCl :NH C1 weight ratiois 1.27:1 to 1.35:1.

4. A galvanizing flux for use as a high-speed continuous galvanizingflux wash consisting essentially of zinc ammonium chloride with a ZnCl:NH Cl weight ratio of from about 1.27:1 to 1:35:l and from about 0.04to 0.4 gram per hundred grams of zinc ammonium chloride, computed assodium salt, of an alkyl sulfonate in which the alkyl groups averageabout 13 carbon atoms and the condensation product of oleyl alcohol withabout 10 mols of ethylene oxide, the ratio of said sulfonate to saidoleyl alcohol condensation product being from 0.2:1 to 4:1.

5. A composition of claim 4 in which the oleyl alcohol is a technicaloleyl alcohol containing alcohols ranging from 8 to 22 carbon atoms.

6. A composition of claim 4 in which the said ratio is 1:1 to 2:1.

No references cited.

DAVID L. RECK, Primary Examiner.

H. F. SAITO, Assistant Examiner.

UNITED STATES PATENT OFFICE CERTHHCATE(HTCORRECTHMN Patent No. 3,321,339May 23, 1967 William A. Schulze It is hereby certified that errorappears in the above numbered patent requiring correction and that thesaid Letters Patent should read as corrected below.

Column 4, line 33, for "znc" read zinc line 34, for "salt of" read salt,of line 47, for "1:35zl" read 1.35:1

Signed and sealed this 9th day of January 1968.

(SEAL) Attest:

EDUUU)J.BRENNER Edward M. Fletcher, Jr.

Commissioner of Patents Attesting Officer

1. A GALVANIZING FLUX CONSISTING ESSENTIALLY OF A FLUXING MATERIALSELECTED FROM THE GROUP CONSISTING OF AMMONIUM CHLORIDE, ZINC CHLORIDE,AND ZNC AMMONIUM CHLORIDE AND 0.04 TO 0.4 GRAM, COMPUTED AS SODIUM SALTOF AN ALKYL SULFONATE PER 100 GRAMS OF SAID FLUXING MATERIAL AND THECONDENSATION PRODUCT OF OLEYL ALCOHOL WITH ABOUT 10 MOLS OF ETHYLENEOXIDE THE RATIO OF SAID SULFONATE TO SAID OLEYL ALCOHOL CONDENSATIONPRODUCT BEING FROM 0.2:1 TO 4:1.